Many industries require material to be transported from one step or operation to another. Such transportation may encompass the product, product and byproduct or just the byproduct. This material transportation may be complex and require a series of steps or it may be as simple as one operation. Often those in industry will use some form of a conveyance system to move these materials around the facility to different operations. Such a system may be composed of a series of conveyor belts and chutes to move the material (e.g., move a package from truck A to truck B). Another such system may entail some type of gravitational feed that transports the material (e.g., move grain from a grain silo through an opening onto a conveyor system and into a rail car).
Two common types of conveyance systems used in industry are mechanical conveyance systems and pneumatic conveyance systems. Mechanical conveyance systems may be comprised of a series of belts, rollers, chains, gravitational rollers, chutes or any other of a number of means to mechanically transport an item from location A to location B. However, mechanical conveyance systems can be prone to dust and dirt due to a lack of not being enclosed. Furthermore, mechanical conveyance systems may not be feasible in some environments because of the space requirements to properly layout the system of rollers, belts, chains, and chutes.
Pneumatic conveyance systems are generally comprised of a series of pipes or duct work that is connected to a vacuum or compressor. Material is sucked or pushed through this duct work from location A to location B. Pneumatic conveyance systems require much less space to operate than mechanical conveyance systems (have smaller foot print). Essentially, a pneumatic conveyance system needs only enough space within which to run the piping for the system. Since pneumatic conveyance systems are completely enclosed they are much better at protecting the material from contamination or conveying a material that can easily become airborne. Therefore, in some environments the pneumatic conveyance system is the only real choice for moving material from location A to location B. However, pneumatic conveyance systems typically have higher energy consumption costs then mechanical conveyance systems due to the way in which they operate.
In the typical pneumatic conveyance system the user is either using pressurized air to push a material through the system or a large vacuum to suck the material through the system. The airflow within the pneumatic conveyance system may move at a rate as fast as 40-45 miles per hour depending on the material moved and do so 24 hours a day. In either configuration there may exist airflow that is not used to move material (waste airflow). In some cases, this waste airflow is vented to the outside air. Alternatively, the waste airflow may be dispersed inside the facility (possibly after further filtration).
With the ever increasing cost of power to industrial users (e.g., cost of electricity per Kilowatt hour, coal cost per ton, natural gas cost per thousand cubic feet) it is essential that those in industry maximize the efficiency of the machines and devices that they utilize in their operations. The increased cost of power will increase the cost of using pneumatic conveyance systems. What is needed is a way to reduce the cost of operating pneumatic conveyance systems and/or a means to recover residual energy from the waste airflow.